Reproduction in Lower and Higher Plants — BIOLOGY STD 12 Science — Question

Your school has been selected by the Department of Education to organise and host an interschool seminar on 'Reproductive Health-Problems and Practices'. However, many parents are reluctant to permit their wards to attend it. Their argument is that the topic is 'too embarrassing'. Put forth four arguments with appropriate reasons and explanations to justify the topic to be very essential and timely.

Long Answer Questions: PKU.

Write on mechanism of opening and closing of stomata.

Study the flow chart given below. Name the hormones involved at each stage and explain their role.

Regulation of breathing.

List the attributes that populations but not individuals possess.

1. Comment on the pattern in which all communities undergo a change in composition and structure with changing environmental conditions.
2. Explain 'Climax community' and 'Sere'.
3. Differentiate between primary and secondary succession with examples.

Complete the table.

Event	Physical process
1. Soaking of Seeds	—————-
2. Water entering guard cells	—————-
3. Exchange of gases	—————
4. Loss of water in liquid form	—————
5. Water coming out through earthen pot	—————
6. Loss of water in vapour form	—————
7. Absorption of solutes passively by carrier	—————
8. Spreading of fragrance of incense stick	—————

STDs are a threat to reproductive health. Describe any two such diseases and suggest preventive measures.

Define transgenic animals. Explain in detail any four areas where they can be utilised.